Cylinder keyway slot plug and extractor



Nov. 5, 1968 H, J BARNES ET AL 3,408,842

CYLINDER KEYWAY SLOT PLUG AND'EXTRACTOR Filed June 28, 1967 Hell INVENTORS DAN EL J.FOOTE ATTORNEYS HYLAND J. BARNES United States Patent 3,408,842 CYLINDER KEYWAY SLOT PLUG AND EXTRACTOR Hyland J. Barnes, Milwaukee, and Daniel J. Foote, Wauwatosa, Wis., assignors to Master Lock Company, Milwaukee, Wis., a corporation of Wisconsin Filed June 28, 1967, Ser. No. 649,613 2 Claims. (Cl. 70424) ABSTRACT OF THE DISCLOSURE There is provided a plug for complete insertion into a lock keyway specially constructed to fit the particular keyway of the lock'into which it is inserted, together with an extractor or plug-removing tool that is notched and shaped complementary to the plug for insertion into the keyway for engagement with the inserted slot plug so that when the extractor or tool is drawn outwardly it will carry with it the keyway plug to thereafter permit operation of the lock by the proper key, entry of the lock by the proper key having been prevented by the inserted plug to forestall opening of the lock by an unauthorized possessor of the lock key.

BACKGROUND OF THE INVENTION Field of the invention Mortise and door locks, night latches, cylinder padlocks and the like are customarily used in hotels, motels, apartment buildings, rooming houses, schools, industrial plants, recreation buildings, etc. to prevent unauthorized entry thereinto, or into closets, compartments, lockers, etc. In many of the examples noted the tenant, guest, traveler, employee, or student who was originally furnished with the proper key for the room, cabinet, closet, locker or other enclosure protected by the lock, may have vacated the premises or severed his connection with the particular organization without turning in the key to the enclosure controlled by the lock. Such unauthorized possessor of the key, if he returns to the premises, could gain unauthorized entry to the locked enclosure or to continue using a locker or the like notwithstanding the fact that he is delinquent in respect to rental or service charges. In such instances it is desirable to provide a means for blocking the keyway in a lock so that the key therefor, when in the possession of some unauthorized person, cannot be inserted into the lock keyway to release the lock. To that end the present invention contemplates the provision of a special keyway plug designed to fit a particular lock keyway, which plug, when lodged within the cylinder keyway, will prevent opening of the lock by the proper key because the key cannot then be inserted into the lock to release it. However, when the superintendent or owner of the establishment containing the locked compartment desires to render the lock operable by the proper key, a properly formed extractor or plugremoving tool can be inserted into the keyway slot plug to engage the latter and withdraw the plug from the keyway. Obviously the plug can be made in any desired form or shape to fit the various keyways made by different manufactures of mortise and door locks, night latches and cylinder padlocks.

SUMMARY OF THE INVENTION A plug, whose particular shape and notched or recessed condiiion is susceptible of great variation to fit any of the types of keyways hereinbefore mentioned is provided, which, when in a proper lock keyway will prevent anyone from inserting the lock key and opening the lock. The plug can be inserted into the lock keyway by hand and pushed fully into position by means of a small 3,408,842 Patented Nov. 5, 1968 instrument or paper clip end, and when in the lock keyway it is held therein by the cylinder pins in the lock. Companion to the plug is an extractor or plug-removing tool specially designed to fit the particular plug under consideration. The extractor, when pushed into engagement with the plug in the keyway, becomes attached thereto and pulls the plug out of the keyway when the extractor is withdrawn.

A general object of the invention is to provide a simple and practical lock keyway plug which will prevent access to the lock by the possessor of the lock key who is presently unauthorized to operate the lock and gain access to the container or compartment controlled by the lock, together with a special extractor or tool, which, when the unauthorized possession of the lock key has passed and access to the container controlled by the lock is in order, permits removal of the plug so that thereafter the lock is operable by its key.

Further objects of the invention are to provide a cylinder keyway slot and extractor of relatively simple construction, which are easy to manipulate, which are adaptable to locks of various types, and which are otherwise particularly well suited for the purposes described.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing, wherein the same reference characters designate the same or similar parts in all of the views:

FIG. 1 is a view, partly broken away and in vertical section, of a lock cylinder keyway with one form of improved plug lodged therein and engaged by a plug extractor;

FIG. 2 is a side view of the form of keyway slot plug shown in FIG. 1;

FIG. 3 is an end view thereof;

FIG. 4 is an end view of a lock cylinder and its keyy;

FIG. 5 is a fragmentary transverse sectional view taken approximately along the line 5-5 of FIG. 1; and

FIG. 6 is a view, partly broken away and in vertical section, of a lock cylinder keyway with another form of improved plug lodged therein and engaged by a modified form of plug extractor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the improved keyway slot plug and extractor can be designed for use in various types of mortise and door locks, night latches, and cylinder padlocks, merely by way of illustration there is shown in FIGS. 1 and 6 of the drawing a lock cylinder 10 having an angular or eccentric keyway 11 therein normally adapted to be entered by the shank portion of a properly shaped key (not shown) so that notches in the particular key will be entered by the yieldingly mounted cylinder pins 12, as is conventional.

The present invention is characterized, however, by the provision of a special form of keyway slot plug 13 which is shaped similarly to the key designed for use in the keyway 11 and is suitably angled and flanged so as to completely fit within the keyway slot 11. The plug 13, designed for a specific keyway slot 11, has a marginal portion thereof provided with recesses 14 corresponding in arrangement to those in the special key for the cylinder keyway 11. This plug 13, besides being angled and flanged to fit the specific keyway slot 11, has a relatively broad head portion 17 which carries the peripheral pin receiving recesses 14 and the end thereof which in use is closest to the access end of the keyway slot 11 is formed as a narrower stem portion 15. In the form of the invention shown in FIGS. 1 and 2, one side margin of the plug stem 15 is provided with a series of shouldered teeth or serrations 16. However, in the alternative form of the invention shown in FIG. 6, both side margins of the plug stem 15 carry serrations 16 and 16'. The broad head portion 17 of the plug 13 is actually like a headless key shank and the entire plug 13, including the broad head the legs 19 merge into an enlarged head 22 to facilitate manual manipulation of the plug extractor. The forward ends of the legs 19 are reduced in width to form fingers 23, and in the form of the invention shown in FIG. 1-, the inner edge of one of the fingers 23 is provided with teeth or serrations 24 which are complementary to and adapted to engage with the teeth or serrations 16 on the edge of the stem 15 of the plug 13. Also, the space between the inner edges of the fingers 23 is enlarged so as to conform to the transverse dimension of the plug stem 15. The extractor legs 19 and fingers 23 have a degree of springiness or yieldability so that when the finger end of the extractor 18 is inserted into the lock keyway 11 for plug removing purposes, said fingers 23 may be spread somewhat so as to straddle the plug stem 15, and. then the inherent yieldability of the extractor legs and fingers will snugly engage the extractor serrations 24 within the complementary plug stem serrations 16, thereby effecting a firm connection as between the finger end of the extractor and the toothed stem portion of the plug. When an outward pull is exerted on the extractor 18 the plug will be released from the yieldingly mounted tumbler pins 12 and can be pulled completely out of the keyway 11, following which the plug and extractor can be disengaged.

While the form of the invention shown in FIG. 1 shows the mating teeth 24 of the extractor fingers and the teeth 16 of the plug stern along a single margin of the stern and extractor fingers respectively, within the purport of the present invention the mating serrations could be on both opposite margins of the plug stern and extractor fingers. FIG. 6 shows this arrangement with the plug stem 15' having serrations 16 and 16 along both of its longitudinal margins to coact with teeth or serrations 24 and 24 on both inner margins of the fingers 23 of the modified form of extractor 18'. Obviously, the teeth or serrations carried by both of the elements may vary in size, shape and disposition.

The improved keyway slot plug and extractor assemblage is primarily intended for use in connection with cylinder pin tumbler or wafer or disc type keyway locks, including key controlled combination padlocks used for school or beach club lockers, or the like. An additional area of utility could be in connection with the ignition lock of a motor vehicle.

The assemblage of the present invention provides a very effective and easily manipulated device susceptible by using the end ofv aninstrument, andlit is held in its fully inserted position within the lock keyway by means of tumbler pinsaThus, anyone having possession of the proper key for the lock but who ispresently unauthorized to use the locker, room or compartment controlled by the lock, cannot operate the'lock. However, an authorized person, 'by utilizing the-companion extractor or release tool, can easily remove the plug by inserting the extractor as previously mentioned, following which said authorized person may unlock the lock with theproper key.

It is to be understood that while preferred embodiments of the invention have-been herein illustrated and described, numerous variations or modifications will undoubtedly occur to those skilled in the art, and it is intended to include herein not only the illustrated forms of the invention but also any and all variations or modifications thereof as may come within the spirit of said invention and within the scope of the appended claims.

We claim:

1. For key blocking insertion into a lock keyway having a predetermined slot and tumbler pin arrangement, the improvements, which comprise: a plug having a portion thereof formed with teeth and generally shaped to conform to the keyway slot and having notches shaped and positioned to receive the lock tumbler pins, and a plug extractor manually engageable with said plug to extract it from the keyway, the extractor being a unitary, bifurcated member having a pair ofyielding legs separated by a slot to receive the toothed portion of the plug with a marginal portion of a leg being formed with teeth, said bifurcated portion of the extractor having a dovetailed engagement with a toothed portion of the plug to releasably interlock with the teeth on said plug portion for extraction of the plug from the keyway.

2. A lock keyway plug and extractor according to claim 1 wherein the notched portion of the plug is a broad head and is formed with a narrow stem for engagement within the bifurcated portion of the extractor, the stem having teeth "along a marginal portion thereof engaged by the leg teeth of the extractor.

References Cited UNITED STATES PATENTS 1,696,326 12/1928 Roethlis'berger --428 2,068,936 1/ 1937 Unterberg 70-428 2,591,652 4/1952 Ziegliss 70-424 X 3,276,233 10/1966 Russell et al. 70428 X 3,338,078 8/1967 Eberitch et al. 70-428 MARVIN A. CHAMPION, Primary Examiner. P. TEITELBAUM, Assistant Examiner. 

